A typical state-of-the-art contactless chip card (also referred to as smartcard) with a mold module 102a (also referred to as chip card module or, for short, module) and an antenna wire 104 is shown in FIG. 1A. The two ends 104_1, 104_2 of the antenna wire 104 are physically attached to the chip card module 102a. This construction has good electrical properties, due to the physical connection of the antenna wires 104 with the module 102a, a low interrogation field strength Hmin and a very high bit rate (VHBR) may be possible.
A disadvantage of the configuration of the smartcard of FIG. 1A may be a limited reliability of the mold module during use, e.g. in the field. In such cards, for example cracks of the mold body or chip cracks caused by overstress (e.g. mishandling by the user) may occur.
In terms of card manufacturing, configuration of the smartcard of FIG. 1A requires a wire crossing (shown in region 104B) to enable a connection of both antenna wire ends 104_1, 104_2 to the module 102a. For this wire crossing, an insulated antenna wire 104 may be required to avoid a short-circuit. The insulated antenna wire 104 may limit a process for forming a wire-module interconnect to welding (a process that is not very reliable, much rework may be required) or to soldering with very high temperatures to remove the insulation by heat. Both processes are disadvantageous for the card structure, they can cause burns in the card material (typically PVC, PC or PET).
A state-of-the-art contactless smartcard with a chip card module 102b having an integrated module antenna 108 for data transmission by inductively coupling to the antenna 104 (a so-called coil-on-module contactless module, COM-CL module) and an antenna wire 104 (also referred to as booster antenna) is shown in FIG. 1B.
The inductive coupling may limit the electrical properties of the smartcard system, so that it may be difficult to find configurations that fulfill the required specifications in terms of low Hmin, VHBR and ISO14443 standard.
The contactless smartcard of FIG. 1B may also require a wire crossing, and hence insulated wire.
The COM-CL smartcard may show good reliability properties. Predicted failure rates for smartcards that are in use (also referred to as field reject rates) may be about 10× smaller than the reject rates of smartcards with mold modules. The good reliability may at least partially originate in the module construction, using a very thin (flexible) semiconductor chip, which may be capable to withstand the mechanical stress in the field.